Eur. Phys. J. D (2012) 66: 68
https://doi.org/10.1140/epjd/e2012-20545-3

Regular Article

Electronic sputtering: angular distributions of (LiF)_nLi⁺ clusters emitted in collisions of Kr (10.1 MeV/u) with LiF single crystals

¹ Centre de Recherche sur les Ions, les Matériaux et la Photonique CIMAP-GANIL (CEA-CNRS-ENSICAEN-UCBN), BP 5133, Boulevard Henri Becquerel, 14070 Caen Cedex 05, France
² Physics Department, Universidade Federal de Santa Catarina, Campus Trindade, 88040-970 Florianópolis, Brazil
³ Physics Department, Pontifícia Universidade Católica do Rio de Janeiro, Rua Marquês de São Vicente 225, Gávea, 22453-900 Rio de Janeiro, Brazil

^a e-mail: rothard@ganil.fr

Received: 21 September 2011
Received in final form: 13 January 2012
Published online: 27 March 2012

Abstract

A combination of imaging techniques (XY) and time-of-flight (TOF) spectroscopy was used to measure the complete velocity vector of sputtered positive secondary ions in collisions of Kr³³⁺ (10.1 MeV/u) with well prepared LiF single crystals in the electronic stopping regime. The angular distributions of (LiF)_nLi⁺ clusters become broader with increasing cluster size n. This could be an indication of contributions from different ejection mechanisms. The experimental secondary ion angular distributions can be fitted by a simple cosine function of the type N(θ) = A cos^m(θ), but it does not reproduce the shape of the jet-like structure observed for the emission of neutral LiF particles perpendicular to the ion beam. Therefore, the cluster emission hypothesis does not explain in a simple way the observed narrow jet.